SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f174486e38635c9f69cffdb0a2e8902bae20e84d5ae9cfcfc808ac2c1b7d1c5' 
  AND token = '0inwoLfloluiwNVagL0ulznDjMsqAAjNIofEPtGHiGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}